wrote:

Meanwhile, I've forgotten a very important detail.
The wall at the moment is bare...no rendering, but I've planned to use
celotex insulation and plasterboard...I guess I'll have to use a
proper studding frame behind the boiler and then look for longer
screws (or these polyester fixings) to account for the thickness of
the studs.

If you are dry lining, then you can make it simple for yourself by
placing noggings in the studwork at the right position to take the
boiler fixings. Then you can use normal screws to attach it without
needing to worry about getting a good fix.

On the other hand, it may seem a bit wacky but what about fixing the
boiler straight to the bare wall and then later on fixing the
insulation and plasterboard all around the boiler? The cold bridge

Not a good idea... will make access to it a PITA, and you may find the
pipe terminations etc do not even clear the surface.


--
Cheers,

John.

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